/**
 * Created by zby on 2018/3/25.
 */
class A3 {
    final double PI = 3.1415926;

    public double getArea(final double r) {
        return PI * r * r;
    }

    public final void speak() {
        System.out.println("您好，How's everthing here ?");
    }
}

public class Example5_9 {
    public static void main(String[] args) {
        A3 a = new A3();
        System.out.println("面积：" + a.getArea(100));
        a.speak();
    }
}
